ABSTRACT The high genetic diversity of porcine reproductive and respiratory syndrome virus (PRRSV) poses a significant challenge to effective vaccination and infection prevention. Recently, NADC30-like PRRSV has become dominant in China. In this study, we characterized a PRRSV isolate XJ2020 from a vaccinated pig. The isolate exhibited moderate pathogenicity in piglets and clustered within the same sub-lineage as NADC30. Sequence analysis identified a unique deletion of the serine residue at position 32 (S32) in the GP5 protein. This deletion was introduced into a highly pathogenic PRRSV (HP-PRRSV) strain, JX2015, to generate the mutant JX2015-ΔS32 using a reverse genetic approach. We found that JX2015-△S32 showed reduced propagation in Marc-145 cells and decreased sensitivity to neutralization by MLV-derived anti-PRRSV positive serum, but exhibited enhance replication in primary porcine alveolar macrophages (PAMs) compared to its parental strain JX2015. Interestingly, the viral load in lung and ileum samples from JX2015-△S32-infected piglets was higher, but the lung injury was milder than in JX2015-infected piglets. Overall, this study highlights the S32 site in the PRRSV GP5 protein as an important factor influencing virus propagation, neutralization, cell tropism and pathogenicity in piglets, and suggests that targeting this residue could lead to the development of more effective PRRSV vaccines.
Xingdong Zhou, Xiaohui Zhang, E. Kan et al.· Virulence· 0 citations
To clarify the genetic evolutionary characteristics of porcine reproductive and respiratory syndrome virus (PRRSV) circulating in northern Xinjiang, China, in 2026, this study employed third-generation sequencing technology to determine the complete genome sequences of locally prevalent PRRSV strains and conducted systematic analyses of their molecular features. Porcine serum samples were collected from pig farms in northern Xinjiang, China, in 2026, and four PRRSV-2-positive samples were identified via fluorescent RT-PCR. Whole-genome sequencing was performed using the CycloneSEQ nanopore single-molecule sequencing platform. After obtaining the complete viral genome sequences, bioinformatics software including MEGA 12, DNASTAR, RDP4, and SimPlot 3.5.1 were used for phylogenetic analysis, homology comparison, key amino acid variation analysis, and recombination event identification. One high-quality complete PRRSV-2 genome sequence, designated XJ/PRRSV-2/2026-1 (15,009 bp in full length), was successfully obtained, along with three additional low-quality sequences used as references. Phylogenetic analysis revealed that all sequences belonged to Sublineage 1.8 (NADC30-like) of PRRSV-2. Homology analysis revealed that this strain shared the highest nucleotide identity (87.5%) with the NADC30 reference strain, with the ORF1a gene exhibiting the most significant variation, particularly within the NSP2 region. Amino acid sequence alignment revealed that the NSP2 region exhibits a discontinuous deletion pattern of "111 + 2+1 + 19", characterized by an additional two-amino-acid deletion at positions 467-468 compared to the typical "111 + 1+19" deletion of NADC30-like strains. Amino acid variations in the GP5 protein were concentrated in the signal peptide region (aa 1-31) and the C-epitope region (aa 53-62), containing three potential N-glycosylation sites (34 NSSS, 44 NLTI, 51 NGTD) and two transmembrane regions. Recombination analysis confirmed that this strain is a recombinant strain derived from NADC30, JXA1, and ATCC VR-2332, with three recombination breakpoints identified. This study presents a whole-genome characterization of an NADC30-like recombinant PRRSV strain detected from northern Xinjiang, China. A novel NSP2 deletion pattern and critical amino acid substitutions in the GP5 protein were identified. These observations are consistent with previous regional molecular epidemiological surveillance and may serve as a basis for broader investigations into the genetic evolution of PRRSV.
Shuhua Liu, Zhen Zhang, Baihe Ma et al.· Microbial Pathogenesis· 0 citations